Dialysis and other forms of blood treatment employ blood treatment devices that are used to remove water and/or other undesired constituents from the blood and restore can also help electrolytes to the blood of patients. Dialyzers, a type of blood treatment device, for example, can replace the natural function of the kidney. In dialysis blood is treated outside of the body of the patient by passing it through a dialyzer. Hemoperfusion is another type of treatment that uses blood treatment devices. Regardless of the type of treatment, a problem with using treatment devices such as blood treatment devices and dialyzers is the presence of air or other gas or gasses in the blood treatment device prior to connection to a patient. If air or other gas or gasses and/or bubbles are present in the blood treatment device, the patient may be injured by air or other gas or gasses embolisms or clot embolisms induced by the air or other gas or gasses in the blood treatment device and tubing. Priming with fluid such as saline is used to remove air or other gas or gasses. Priming techniques on dialysis blood lines and blood treatment devices includes pumping the priming fluid through the circuit, hammering, inverting, and shaking the blood treatment device while flowing fluid through it in order to remove the air or other gas or gasses and/or bubbles. Automated systems that can be used for priming are also known, but they can inconvenient if it is desired to prime a blood treatment device to permit it to stand by for replacement in a system being used for treatment. Also existing automated systems may tie up the treatment system or be complex. Dialyzers and other blood treatment devices are commonly sold as standalone products and have labeling that prescribes the amount of saline that must be used to prime. The users are obliged to follow these instructions, making replacing a blood treatment device during a therapy session very difficult, if not impossible since blood is already in the blood tubing circuit and in the blood treatment device to be replaced. Also, many Continuous Renal Replacement Therapy (CRRT) machines have a preconnected and bonded in place blood treatment device, making replacement of the blood treatment device impossible. The CRRT disposable consists of a blood treatment device, a blood line portion and a therapy fluid portion. During a therapy session, sometimes the blood treatment device becomes exhausted and clogged, but the rest of the disposable circuit is still useable. An option is to discard the entire circuit. This takes therapy time away from the patient as the circuit is swapped, primed, and tested prior to reinitiating the therapy, and a substantial portion of the disposable cost is the non-blood treatment device portion.